Our overall objective is to understand how the receptors for the sex steroid hormones are regulated in human endometrium and how this determines the responsiveness of this tissue to estrogens and progestins. Utilizing primary mixed cell cultures and cultures of separated epithelial and stromal cells from relatively normal human endometrium, we will determine the effects of estrogens on cellular estrogen and progesterone receptor levels, on intracellular receptor dynamics and cell proliferation, on the induced synthesis of cellular and secreted proteins, and on the stimulation of certain enzymes including peroxidase, plasminogen activator, ornithine decarboxylase, and glucose-6-phosphate dehydrogenase that we feel will be good markers for estrogen action in the human uterus. We will also examine intracellular progesterone receptor dynamics and the possible modulation and/or termination of estrogen-stimulated events by progestins, and evaluate possible hormonal interactions between epithelium and stroma. We will also work to develop and characterize long-term, permanent cell lines from endometrial adenocarcinomas to enable comparisons of hormonal regulation of proliferation and function of endometrial adenocarcinoma versus normal endometrium, and their relationship to the presence of intact estrogen and progesterone receptor systems. The unique feature of this in vitro system is that it enables studies to be done directly on human endometrial target cells and therefore eliminates the necessity of extrapolating to human tissue information obtained with experimental animal systems and obviates the difficulties inherent in obtaining quantitative information about human reproduction from in vivo studies. Our findings should provide direct information on the hormonal sensitivities and responses of endometrial epithelium and stroma, individually and collectively, to natural and synthetic estrogens and progestins, and should enable significant progress to be made in understanding how the sex steroid hormones regulate uterine function, and the bases of sensitivity and resistance to endocrine therapy in adenocarcinoma of the uterus.